Revert "improve labpack processing"
Revert "improve labpack processing"

This reverts commit c4dd47aa99ea32acacc55fa793d7a5764b3a4aa8.

jcupitt/libvips,lovell/libvips,lovell/libvips,jcupitt/libvips,lovell/libvips,jcupitt/libvips,lovell/libvips,jcupitt/libvips